I have a 98 camaro with the 3.8L engine. I bought the pacesetter headers and I noticed a spot for an oxygen sensor right before the cat. I was just under a 2000 camaro same engine but couldn't find the sensor. My question is am I blind or is the only sensors are in the exhaust manifolds and after the cat?

 

For the 02 sensor to work properly you need it to be in the full exhaust stream, that is why the bung for the sensor is in the collector. On the manifolds the bung is in the area where all 3 ports come together. The one after the cat determines if the cat is good or not.

Massey